The use of gas expandable airbags for protecting vehicle occupants is well established. These devices, which inflate upon actuation by a crash sensor, have proven very effective in protecting the driver and front seat passenger. Such a device is in the form of a balloon-like bag positioned to receive the impact of the head and upper torso. The head and upper torso present a relatively large impact area and its impact energy is well-absorbed by such a device.
It would be desirable, however, to provide an inflatable restraint device which would be capable of absorbing a more concentrated force. One example of such a requirement would be a knee bolster. The knee, being a relatively small area object, imparts its kinetic energy into a concentrated area. A single airbag would need to be very large and stiff to properly manage such an impact.
A second application which would be difficult to implement using conventional airbags involves side impacts. Passengers involved in such impacts require protection from relatively large surface areas of the vehicle such as side pillars and doors.
It would also be desirable to provide a device which would inherently have built-in crash protection to a certain degree, even in the absence of inflation. In such a device, the degree of inflation could be varied to alter the degree of protection afforded.
Accordingly, it is a primary object of the present invention to provide an inflatable crash protection device which is capable of handling concentrated impact loads. Another object of this invention is to provide such an apparatus which can cover a relatively large area. Another object is to provide such a device which has an energy-absorbing structure, even in the absence of inflation. Other objects, features, and advantages will become apparent from the following description and appended claims.